一种用于干涉型光纤传感器动态相移测量的J0-J1法

提出了一种用于干涉型光纤传感器动态相移测量的J0-J1法,实现了无源零差检测,而且信号解调算法简单,检测频带宽。详细介绍了该方法的基本检测原理,并对解调误差进行了理论分析与仿真,得出了系统能够检测的最大动态相移幅度与干涉仪的工作点允许变化的范围相互制约的结论。编写了实时的信号采集、处理程序,对某一干涉型光纤水听器探头的声压灵敏度进行了测量。在频带20~1300Hz上,平均声压灵敏度为-162dB(0dB=1rad/μPa),波动<±1.0dB,单频点500Hz的灵敏度变化<±0.5dB,与采用相位载波(PGC)调制解调法测量的结果基本一致,验证了J0-J1法的可行性。

A J0-J1 Method for Measurement of Dynamic Phase Changes in an Interferometric Fiber Sensor

A J0-J1 method for measurement of dynamic phase changes in an interferometric optical fiber sensor is described. This method has the advantages of no electric elements in the sensing head and the simplicity of signal processing. The detection principle of this method is introduced in details. The demodulation error is analyzed and simulated theoretically. The measurable amplitude of the dynamic phase change and the permitted varying range of the work-point restrict each other. A system of data acquisition and processing is programmed, and an interferometric fiber-optic hydrophone is tested. The average acoustic pressure sensitivity is -162 dB (0 dB=1 rad/μPa) over the frequency range of 20 Hz to 1300 Hz, the fluctuation is smaller than ±1.0 dB, and the change at 500 Hz is smaller than ±0.5 dB, which accords well with the results obtained with the method of phase generated carrier (PGC) modulation and demodulation. The experimental results prove that this J0-J1 method is feasible.